Voters across Spain are casting their ballots for the second time in six months in an attempt to resolve the political stalemate that has beset the country since last December’s inconclusive general election, potentially delivering a fresh jolt to Europe’s political mainstream after Britain voted to leave the European Union.

The last election broke the mould of 40 years of stable conservative or Socialist majorities and failed to produce a government resulting in a hung parliament. Although there is increasing public frustration over the deadlock and the growing resentment of the establishment following an economic crisis, polls suggest the new elections are likely to yield a similar result to last time, with no single party winning enough votes to form a majority government.

Opinion polls suggest the parliament that emerges this time will be just as fragmented as the previous one. Four big parties and six smaller regional ones are likely to win seats in the 350-strong assembly, none of them coming close to a majority.

It also remains to be seen how profoundly Sunday’s poll - the first major European election since the UK voted to leave the EU - will be affected by Brexit, and whether Spaniards will seek reassurance by backing the conservative People’s Party (PP), or opt for a new alternative.

“It is really important to convey a message of institutional and economic stability,” said acting prime minister and PP head Mariano Rajoy in a televised address after Britain voted to leave. “It is not the moment to fuel or increase uncertainty.”

In December the PP gained the most votes but fell short of the 176 seats required to secure a majority in Spain’s 350-seat congress of deputies. The socialist PSOE came second, followed by the leftwing, anti-austerity party Podemos and the centrist Ciudadanos, or Citizens, party.

The votes attracted by the latter two parties – newcomers to a political scene that has been dominated for decades by the conservatives and the socialists – revealed a profound shift among an electorate that has been buffeted by Spain’s economic crisis and angered by a series of corruption scandals that have engulfed the PP in recent years.

Polls suggest Podemos’s decision to forge an alliance with the United Left (IU) coalition, whose members include the Communist party of Spain, could lift it above the PSOE into second place.

Some voters said on Sunday they went for a "safe option" by backing the historically dominant PP and PSOE. Others said they were encouraged to vote for the insurgent Podemos

A poll published late on Saturday night in the Andorra-based paper Periòdic d’Andorra, which is not affected by Spain’s ban on publishing surveys in the five days before the vote, showed the PP ahead on 28.7% of the vote (116-120 seats), and the PSOE and Unidos Podemos almost neck-and-neck with 21.6% (83-87 seats) and 23.9% (83-87 seats) respectively. It suggests that a coalition between the two left parties could yield 174 seats - tantalisingly close to a majority.